Introduction

1
Chapter 1

• Introduction

2
Descriptive vs. Inferential Statements

• Descriptive statements are statements of facts.
• Inferential statements are statements of opinions
  and predictions.

3
Populations vs. Samples

• A population consists of every item possessing a
  specific set of characteristics.
  
• A sample is a small group of items chosen from
  within a population. Samples let us study the
  properties of a population when studying the
  entire population is not possible.

4
Parameters vs. Statistics

• Parameters are calculations based on the
  measurements of an entire population.
  
• Statistics are calculations based on the
  measurements of a sample.
  
• Statistics are used to infer information about
  parameters.

5
Data Types

• Discrete data can only take on certain
  disconnected values.
  
• Continuous data can take on any number in a given
  interval. The accuracy of the measurement is
  limited only by the accuracy of the measuring
  tool.
• Proportional data are relative measures, such as
  percentages.

6
Finite vs. Infinite Populations

• A population is finite if it contains a countable
  number of items.
  
• A population is infinite if there is no end to
  the items it contains.

7
Population or Sample?

• The average test scores of 10 statistics students
  used to represent a class average.
  
• SAMPLE

8
Population or Sample?

• The mileage readings of the odometers of all the
  company cars of ABC Inc. company.
  
• POPULATION

9
Descriptive or Inferential?

• The average SAT score of the 1996 incoming
  freshmen class, at a local college, was found to
  be 880.
  
• DESCRIPTIVE

10
Descriptive or Inferential?

• Using the daily sales data from several of the
  large retail stores for the first week of
  December, the manager of a mall predicts that the
  Christmas shopping season will be better than the
  previous year.
• INFERENTIAL

11
Discrete, Continuous, or Proportional?

• The number of pieces of luggage each passenger
  carried onto a particular flight out of San Diego
  Airport.
  
• DISCRETE

12
Discrete, Continuous, or Proportional?

• The total weight of 150 passengers and their
  luggage on a Southwest Airlines flight from San
  Diego to Las Vegas.
  
• CONTINUOUS

13
Discrete, Continuous, or Proportional?

• The proportion of SDSU students who crashed a
  class last semester.
  
• PROPORTIONAL